The present invention relates to an optical device module incorporated in digital cameras, camera phones and the like and having a solid-state image sensor for photographing a subject, and a method of fabricating the optical device module.
A solid-state image sensor provided in digital cameras, digital video cameras, camera phones and the like is for capturing the subject to be photographed. The solid-state image sensor is integrated into a module together with a lens, an infrared intercepting material and a signal processor processing the electric signal converted from captured image by the image sensor, and is provided as an optical device module. In recent years, digital cameras, camera phones and the like incorporating the optical device module have been reduced in size, and the optical device module has also been reduced in size.
In the optical device module, it is necessary that the optical center of the image sensing area of the solid-state image sensor coincide with the optical center of the lens, and it is also necessary that the plane formed by the image sensing surface be orthogonal to the optical axis of the lens. When the accuracy of the alignment of the lens' axis with the sensor's center is low, a problem occurs such that focus cannot be achieved or that the image captured by the solid-state image sensor is dark. For this reason, an adjustment mechanism for adjusting focus is provided, and focus adjustment is performed after the optical device module is fabricated. However, the provision of the adjustment mechanism hinders the size reduction of the optical device module.
Japanese Patent Application Laid-Open No. 2000-125212 proposes an imaging module in which a semiconductor chip where a solid-state image sensor is formed is bonded onto a ceramic board, a frame material holding an infrared intercepting material is bonded onto the ceramic board so as to cover the semiconductor chip and a lens frame material holding a lens is bonded onto the ceramic board so as to cover the frame material. By bonding the semiconductor chip, the frame material and the lens frame material onto the same plane of the ceramic board, their alignment accuracy is improved.
Japanese Patent Application Laid-Open No. 2004-40287 proposes an image sensor module in which an image sensor chip is bonded onto a board, a housing holding a lens and an optical filter is bonded onto the board so as to cover the image sensor and the lens is pressed into the housing by a lens retainer that becomes elastically deformed. By fixing the lens in the housing by the lens retainer, the distance between the lens and the image sensor can be accurately defined.
Japanese Patent Application Laid-Open No. 2004-301938 proposes an optical device module in which a signal processor that processes signals outputted from a solid-state image sensor is bonded to a wiring board, the solid-state image sensor is bonded onto the signal processor, a transparent lid is bonded to a surface of the solid-state image sensor and a lens holder holding a lens is bonded to the transparent lid. Since the lens holder is bonded to the transparent lid bonded to the surface of the solid-state image sensor, the accuracy of the alignment of the lens with respect to the solid-state image sensor can be improved.